What are the best iPhone apps to do with guitars? Whether it be a chromatic tuner, scales etc

I need a few for my new iPhone.

erm.. UG tools
My Rig
Fender Blacktop Strat HH MN > Joyo JF-01 Vintage Overdrive > Boss ME50 > Line 6 Spider IV 30

Other Shit
Jim Deacon Acoustic
Yamaha 12 string acoustic

New Amp Fund
I use Guitar Pro for tabs and AnyTune Pro for playing along and learning songs.

Anytune et's u change the pitch and speed of the song (from ur iTunes library). You can loop sections and slow them down - and change the pitch to match ur guitar tuning.

I use (free) drum apps from here http://www.freedrumapps.com/Site/Apps.html